Method of casting link-type insulators



1929- M. F. H. GOUVERNEUR ET AL ,7

METHOD OF CASTING LINK TYPE INSULATORS Filed Dec. 11, 1924 Patented Oct. 29, 1929 UNITED STATES CORPORATION or MARYLAND AT T; ZT

JMEINOR F. 'H. GOUVEBNEUR A D FRANK J. srnvnns, OFBALTIMORE, MARYLAND,

nssrenons T0 LOCKE INSULATOR CORPORATION, or

METHOD OF CASTING LINKTYIPE INSULATORS Application filed December 11, 1924. Serial No. 755,279.

have been almost universally formed by sub jecting plastic porcelain clay to pressure in a centering press, but'the difference in the rate of drying of unequal thicknesses of, clay has necessarily limited the product so formed to very small variations in thickness and hence limited this spacing of the parts of op 'posite potential to a minimum. Numerous efforts have been made to cast insulators of this type but have for themost part been unsuccessful since heretofore no method has been devised by which the opening could be formed in the insulator without detriment to the finished insulator. i

The object of the invention, more particularly stated, is to provide a method of making a link type insulator by casting'it about a previously inade hollow core element in such position Within a suitable" mold of a porous nature that substantially all the surfaces will be in contact with the walls of the mold at the same time and consequently dry uniformly, thus avoiding unequal strains' After the casting has dried to the so-called leather-dry state it is removed from the moldand drilled or otherwise formed with a hole concentric with the bight of the U-shaped core element to define a link, and the other finishing steps, such as shaping the surfaces, dressing out of the 'holes'and the entrances to the core member, are performed.

To the attainment of the foregoing and other objects and advantages, the invention consists in the various steps and the utilization of the mold members to be hereinafter more fully described and pointed out in the claims hereunto appended.

section.

In the drawings:

Figure 1 is a faceview of one section of a split mold for forming the U-shaped tubular coreelement, the cast core beingshown in bllicli qure 2 is a plan view of the moldasseme i i Figure 3 is a vertical section through the separable mold for forming the insulator, the core element being shown in position and the insulator body moldedthereabout. Figure lis an elevation looking at one side of the mold. ,Figure 5 is a cross section through the finished insulator.

Figure 6 is a section therethroughonthe line 6-6 of Figure 5. i

Throughout the drawings" like parts are designated by like reference characters.

. The first step involved in the actual carrying out of the method consists in formingia 'U-shaped tubular or hollow core element. To accomplish this, a split mold shown in .Fig-

ures 1 and 2 is emplo ed, this mold including similar sections 1 and 2 having complementary or mating U-shaped recesses 'or cavities 3 therein which define a U-shaped passage when the sections are assembled and held by any desired means, notshown. The plastic material, such as porcelain clay in a fluid state, is poured into thismold and is allowed to stand for a suflicient length of time to permit it to solidify to the desired thick ness at the area of contactwith the mold,

after which the still fluid center of the mass is poured out. The result is the formation of a U-shaped tube 4, which is permitted to set until it maysafely be removed from the mold without distortion. While wehave, to clearly illustratethe invention, shown the tube 4 as a separate element in the finished insulator, it will be understood that such is not the case BALTIMORE, MARYLAND,

and the tubeand insulator core are in reality a one. t a

The second step involves the employment of a mold including members '5 and 6, the latter of which has a cavity? therein cor responding in shape to the top of theing sulator, and the former of which is plane and formed with a pair of spaced holes 8 of sufficient size to receive the ends of the above described U-shaped tube or core t. If there are any spaces about the tube ends, such gaps or spaces may be plugged, from either side, with wet clay or other similar material to avoid leakage at the joints. If desired or essential, a centering device or other means ma be utilized for holding the tubular core in the proper position, though such is not illustrated. The mold sections'or members 5 and 6 are placed together, or assembled, and held by any conventional or preferred means, as is customary in the molding or casting art. To form the insulator, porcelain clay in a fluid state, or other suitable plastic material, is introduced through the gate 9 and will naturallyflow. into the cavity 7 and mold itself about the tube to form the piece or body indicated at 10. It is preferable that the gate be of sufficient size that only one filling will be necessary. The fluid or plastic material dries first wherever it comes in contact with the mold, while the center of the piece remains quite soft or even possibly semi-liquid fora time and is filled, as shrinkage takes place, from the surplus contained within the gate,

Ordinarily, the'ends of the tube 4 may be left open and as the tube is porous it will conduct away the moisture and dissipate it into the atmosphere, thereby assisting the molded piece in drying at its thickest portion, the

center. Shouldit be found advisable to check or prolong the drying, the ends of the tube may be plugged with wet clay as indicated at 11. If a quicker setting is desired, a forced draft may be introduced through the tube 4 by any suitable means. Attention is directed to the fact that as the fluid material sets almost instantly wherever it contacts with the .mol'd, the joints therein will be filled and effectually sealed. As both sides of the piece which constitute the top and bottom surfaces of the, insulator engage the mold at the same time, it is evident that the setting will be uni form so that stresses and strains from unequal drying will be entirely avoided. Vi e have also found that the fluid material enters the pores of the tube and causes such an intimate union or amalgamation therewith that the tube becomes an integral part of the whole.

After the piece has set to a sufficient extent it is removed from the mold and the projecting ends of the tube 4 sheared off. If, during setting, the ends of the tube should shrink together no objectionable results would occur as these ends are to be severed any way. After drying in any ordinary or preferred manner,

the entrances to the tube are dressed out in a funnelshape, as shown at 12 in Figure 5', and the under surface of the piece is dressed off as for instance as illustrated at 13, or treated to have anyspecific shape preferred, though it is intended that a water drip 14 be provided at the outer edge.

After the piece has been partially dried, a hole 15 is drilled, punched or otherwise formed concentric with the bight portion of the tube 4 and at right angles to the plane thereof, and the ends of this hole are reamed or dressed out in a funnel-shape, as shown at 16 in Figure 6. It will be observed that the hole formed by the tube 4 is a full semicircle whose center coincides with the center of the hole 15. The shape of the dressed hole 15 with its'funnel-shaped ends 16 is such as to provide a semi-circular area where contact occurs between the porcelain and the connecting link, not shown, with which the insulator is associated.

e claim: 7

1. The method of making a link insulator,

consisting in forming a porous tubular core element having spaced arms connected by a curved bight portion, and molding an insulater, body about the core, the core element having its ends projecting beyond said body and open to serve as a drying fine.

2. The method of making an insulator consisting in forming a substantially U-shaped tubular porous coreelement. molding the insulator about said corejelement, the ends of the latter being exposed and open whereby it may be utilized as an air fine for drying the center of the piece.

3. The method of making an insulator, comprising forming a curved tubular porous core, castingthe insulator body about the core with the ends of the core exposed, and controlling passage of air through the core for regulating the rate of drying of the cast material.

4. The method of making an insulator comprising; forming a porous tube and casting the insulator body aboutthe tube with the ends of the tube exposed whereby the tube serves as a line having controllable communication with the atmosphere whereby the rate of evaporation of moisture passing through the walls of the tube from the cast mater al may be regulated.

5. The method of making an insulator comprising forminga tubular core of porous material, casting the insulator body about said tube with the ends thereof exposed to the atmosphere. and creating a forced draft through the tube for facilitating evaporation of moisture passing from the cast material through the wall of the tube.

In testimony whereof we our signatures.

FRANK J. STEVENS. MINOR F. H. GQUVERNEUR. 

